Marianne Strickrodt

Introduction

When exploring our everyday environment we experience many interconnected spaces, e.g., hallways and rooms forming the ground floor of a building. Although such environmental spaces cannot be overseen from a single vantage point, but instead are bound to a piecewise learning experience, we are capable of building a mental representation of it. Theories that postulate a hierarchical representation of our environment [1] assume that subsets of input units are grouped together, and subsumed under a unit on a higher level of hierarchy. However, the nature of spatial units as well as the circumstances under which grouping into higher order units occur is still unexplored.

Goals

We investigate how humans encode, represent and recall environmental space. Our research questions are concerned with how environmental space memory is different from spatial memory acquired in a single room from one vantage point, also called vista space, and with the nature of a higher order spatial unit, that subsumes multiple vista spaces.

Figure 1. Left: Object array in environmental space from a birds‑eye perspective and participants view from within the environment. Right: Array and participants view within vista space. Grey arrows above the Xs indicate the initial view in the environments.

Methods

In our tracking lab, participants explore large virtual environments. This setup allows them to actively walk through the virtual world presented via a portable head mounted display. Subsequently, we test their spatial memory with a range of tasks, such as pointing to distant targets from memory, or reproducing previously learned spatial arrangements.

Initial results

We have shown that the representation of an environmental space differs from the representation of a vista space in terms of their reference frames (i.e., mental coordinate system storing configurations between landmarks). Further, our results suggest that recalling environmental spaces follows a piecewise (unit by unit) rather than an immediate, comprehensive memory access of the entire space that was memorized [2]. Results of another study indicate that higher order mental units that subsume multiple vista spaces can be formed and can be of spatial nature, i.e., a reference frame that spans objects located in multiple vista spaces [3].

Initial conclusion

Opaque borders (walls) that section environmental space into vista spaces seem to elicit a clustered representation, potentially consisting of vista space units, that renders the memory for environmental space fundamentally different from the memory of a vista space. Nevertheless, subsuming those units under a common, global mental coordinate system seems to occur, conceivably on a higher level of a hierarchical representation. In a next step, we will explore whether people also form a globally consistent survey representation when (unknowingly) confronted with a globally inconsistent, impossible space.